22 research outputs found

    Generalized vector valued almost periodic and ergodic distributions

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    For \Cal A\subset L^1_{loc}(\Bbb J,X) let \Cal M\Cal A consist of all f∈Lloc1f\in L^1_{loc} with M_h f (\cdot):=\frac {1}{h}\int_{0}^{h}f(\cdot +s)\,ds \in \Cal A for all h>0h>0. Here XX is a Banach space, J=(α,∞),[α,∞)\Bbb J= (\alpha ,\infty), [\alpha ,\infty) or R\Bbb R. Usually \Cal A\subset\Cal M\Cal A\subset \Cal M^2\Cal A\subset .... The map \Cal A \to \Cal {D}'_{\Cal A} is iteration complete, that is \Cal {D}'_{\Cal {D}'_{\Cal A}}= \Cal {D}'_{\Cal A}. Under suitable assumptions \widetilde {\Cal M}^n \Cal {A}= \Cal A + \{T^{(n)} : T \in \Cal A\}, and similarly for \Cal {M}^n \Cal A. Almost periodic XX-valued distributions \h'_{\A} with \A = almost periodic (ap) functions are characterized in several ways. Various generalizations of the Bohl-Bohr-Kadets theorem on the almost periodicity of the indefinite integral of an ap or almost automorphic function are obtained. On \Cal {D}'_{\Cal E} , \Cal E the class of ergodic functions, a mean can be constructed which gives Fourier series. Special cases of \Cal A are the Bohr ap, Stepanoff ap, almost automorphic, asymptotically ap, Eberlein weakly ap, pseudo ap and (totally) ergodic functions (\T)\E. Then always \Cal {M}^n \Cal A is strictly contained in \Cal {M}^{n+1} \Cal A. The relations between \m^n \E, \m^n\T\E and subclasses are discussed. For many of the above results a new (Δ)(\Delta)-condition is needed, we show that it holds for most of the \A needed in applications. Also, we obtain new tauberian theorems for f∈Lloc1(J,X)f\in L^1_{loc}(\Bbb J,X) to belong to a class \A which are decisive in describing the asymptotic behavior of unbounded solutions of many abstract differential-integral equations. This generalizes various recent resultsComment: 69 page
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